1. Field of the Invention
The present invention relates to a recording method for performing recording by ejecting a liquid droplet such as an ink droplet from multiple ejection orifices of a liquid ejection head.
2. Description of the Related Art
An ink jet recording apparatus is a recording apparatus which can output a high-quality letter or image at low cost. As an example, an air bubble generated when a pulse signal is input to an electrothermal converter causes a liquid droplet of black ink or a liquid droplet of color ink of cyan, magenta, yellow, or the like to be ejected from an ejection orifice.
Black ink is often used for, in addition to recording of letters and the like, solid filling of an entire surface of a predetermined region, that is, so-called solid printing. When solid printing is performed by ejecting minute liquid droplets, the number of the ejection times tends to be large and the time required for the recording tends to be long. Therefore, there has been proposed a liquid ejection head in which a liquid droplet of black ink is formed so as to be larger than a liquid droplet of color ink when ejected, which is disclosed in Japanese Patent Application Laid-Open No. 2002-154208.
In the liquid ejection head disclosed in Japanese Patent Application Laid-Open No. 2002-154208, by increasing the moving speed of a carriage having a liquid ejection head mounted thereon, the speed of ink jet recording including the above-mentioned solid printing can be further increased. However, there is a high risk that high-speed movement of the carriage involves image quality deterioration. Generally, a liquid droplet ejected from an ejection orifice includes a main droplet and an accompanying satellite. As the moving speed of the carriage becomes higher, the travelling distance of the carriage from the impact of a main droplet on a medium surface to the impact of its satellite on the medium surface becomes larger. Therefore, there is a tendency that, as the moving speed of the carriage becomes higher, the distance between a main droplet and its satellite becomes larger. As a result, a satellite impacts away from the main droplet which forms a letter, and thus, the image quality at the edge of the letter is conspicuously deteriorated. In the following, defected impact at the edge is described with reference to FIGS. 10A to 10G and FIGS. 11A and 11B. FIGS. 10A to 10G illustrate states from the ejection of an ink droplet to the impacts of the ink droplet on a recording medium. FIGS. 11A and 11B illustrate image quality deterioration involved in high-speed movement of a carriage. FIG. 10A illustrates a state immediately after a main droplet 110 and a satellite 120 are ejected from an ejection orifice 10. FIGS. 10B and 10C illustrate states in which the main droplet 110 and the satellite 120 impact on a recording medium 15 when the moving speed of the carriage is 25 inch/s (0.635 m/s). FIG. 10D illustrates the main droplet 110 and the satellite 120 illustrated in FIG. 10C seen from above. FIGS. 10E and 10F illustrate states in which the main droplet 110 and the satellite 120 impact on the recording medium 15 when the moving speed of the carriage is 40 inch/s (1.016 m/s) or more. FIG. 10G illustrates the main droplet 110 and the satellite 120 illustrated in FIG. 10F seen from above. The ink droplet ejected from the ejection orifice 10 toward the recording medium 15 is divided into the main droplet 110 and multiple satellites 120a and 120b (see FIGS. 10B and 10E). After that, the ink droplet impacts on the recording medium 15 separately as the main droplet 110 and one large satellite 120 which is an aggregation of the multiple satellites 120a and 120b (see FIGS. 10C and 10F). The impact deviation in position of the satellite 120 from the main droplet 110 is caused by the movement of the carriage. When the moving speed of the carriage is about 25 inch/s (0.635 m/s) as in a conventional case, as illustrated in FIG. 10D, an impact deviation L is small and no problem is presented. On the other hand, when the moving speed of the carriage is 40 inch/s (1.016 m/s) or more, as illustrated in FIG. 10G, the impact deviation L becomes larger. Therefore, a non-image area is formed between an area on which the main droplet 110 impacts and an area on which the satellite 120 impacts. The non-image area is recognized more as a lack of sharpness of letter quality, that is, roughness of edges 51, as the area of white, which is the color of the medium surface, becomes larger (see FIGS. 11A and 11B).
Therefore, conventionally, it has been difficult to accomplish high-speed recording and high-quality recording at the same time.